See more from Ask Carzone 
When to change an A4's belt?
Mileage to change timing belt on a 161 A4 avant
Our answer:
Hi Mark,
Assuming it has a 2.0 TDI engine, then it should be at least every 210,000km, regardless of time.
Have a motoring question? Ask us here!
Ask us anything motoring related and please provide as much information as possible so we can give you the most accurate advice.